The present invention relates to information storage apparatuses and methods of controlling the same, and more particularly to an information storage apparatus which records information on a recording medium and a method of controlling the same.
In an information storage apparatus such as a magnetic disk unit or a magneto-optical disk unit, a variety of variable control parameters such as a threshold for signal detection and a light-emitting power of a laser beam are set to their optimum values at times of recording and reproduction. The light-emitting power of the laser beam is controlled based on the set parameters so that the recording and reproduction are performed in an optimum state. Here, a description will be given of a magnetic disk unit serving as an information storage apparatus.
FIG. 1 is a block diagram of a conventional magnetic disk unit.
According to a magnetic disk unit 1, a magnetic head 4 opposes a magnetic disk 2 which is rotated by a spindle motor 3, so that the magnetic disk 2 is magnetized by a magnetic field produced around the magnetic head 4. Thereby, information is recorded on the magnetic disk 2. On the other hand, information recorded on the magnetic disk 2 is reproduced by detecting variations in magnetization of the magnetic disk 2.
The magnetic head 4 is supported at the tip of an arm 5 and opposes the magnetic disk 2, the magnetic head 4 being floated slightly above the magnetic disk 2 by an air current produced by rotations of the magnetic disk 2. The arm 5 is held so as to turn freely around a shaft 6. The other end of the arm 5 is linked to a voice coil motor 7. The voice coil motor 7 turns the arm 5 in a radial direction (direction indicated by arrow A) of the magnetic disk 2 around the shaft 6.
The magnetic head 4 is connected to a head IC 8. The head IC 8 amplifies a recording signal supplied to the magnetic head 4 and a reproduced signal reproduced by the magnetic head 4.
The head IC 8 is connected to a read channel (RDC) IC 9 and to a servo information demodulation circuit 10. The read channel IC 9 demodulates the reproduced signal supplied from the head IC 8 to its original data, and modulates recording data to be recorded on the magnetic disk 2 to generate the recording signal. The servo information demodulation circuit 10 extracts servo information from the reproduced signal supplied from the head IC 8 and demodulates the extracted servo information.
The reproduced data demodulated in the read channel IC 9 is supplied to a hard disk control IC (HDC) 11. The hard disk control IC 11 retains the reproduced data in a memory 12 and transfers the retained reproduced data to a host computer via an interface. The hard disk control IC 11 temporarily stores in the memory 12 the recording data supplied from the host computer via the interface, and supplies the stored recording data to the read channel IC 9.
The read channel IC 9 and the hard disk control IC 11 are connected to an MCU 14. The servo information demodulation circuit 10 and a digital signal processor (DSP) 17 are connected to the MCU 14 via a gate array 16.
The MCU 14 controls operations of the head IC 8, the read channel IC 9, the servo information demodulation circuit 10, and the digital signal processor (DSP) 17 based on a control program and control parameters stored in a memory 15.
A driver IC 18 is connected to the digital signal processing circuit 17. The driver IC 18 generates, based on a control signal supplied from the digital signal processor 17, driving signals which drive the voice coil motor 7 and the spindle motor 3, respectively. The voice coil motor 7 is driven based on the driving signal supplied from the driver IC 18 to move the magnetic head 4 in the radial directions of the magnetic disk 2, that is, in the direction indicated by the arrow A. The spindle motor 3 is driven by the driving signal supplied from the driver IC 18 to rotate the magnetic disk 2 on a shaft 19.
A temperature sensor 20 is connected to the MCU 14. The temperature sensor 20 detects an ambient temperature of the magnetic disk 2. A temperature detected by the temperature sensor 20 is supplied to the DSP 17 via the gate array 16. The MCU 14 controls the control parameters supplied to the read channel IC 9, the head IC4, the servo information demodulation circuit 10, and the DSP 17 based on, for instance, a generated error or the temperature detected by the temperature sensor 20.
At this time, the control parameters supplied to the read channel IC 9, the servo information demodulation circuit 10, and the DSP 17 are stored in the memory 15. When a write command and a read command are supplied to the MCU 14 from the host computer, the MCU 14 reads out the control parameters from the memory 15 based on the control program, and supplies the control parameters to the respective circuits. The main control parameters are a servo parameter and read and write parameters.
FIG. 2 is an operational flowchart of an MCU of the conventional magnetic disk unit at a time of a read/write operation.
When supplied with a write or read command from the host computer (step S1-1), the MCU 14 supplies servo parameters that are control parameters, one byte at a time, that is, one word at a time, from the memory 15 to the servo information demodulation circuit 10 and the digital signal processor 17 (steps S1-2 and S1-3). The servo parameters are parameters that control a driving of the voice coil motor 7 and a reading of servo information at a time of, for instance, a tracking jump.
When the servo parameters are supplied to the servo information demodulation circuit 10 and to the digital signal processor 17 in step S1-3 (steps S1-4 and S1-5), the MCU 14 starts a seek operation to a head number X and a cylinder number Y specified by the write or read command supplied from the host computer (step S1-6).
When the seek operation to the given head number X and cylinder number Y is started in step S1-6, read or write (read/write) parameters that are control parameters are supplied to the read channel 9 one byte at a time, that is, one word at a time (step S1-7). The read/write parameters are parameters that control signal reading and writing states.
When the read/write parameters are set in the read channel IC 9 in step S1-7 (steps S1-8 and S1-9), and the seek operation to the head number X and cylinder number Y specified by the write or read command supplied from the host computer is completed (step S1-10), a read/write operation is performed (step S1-11).
In the conventional magnetic disk unit, the transfers of the control parameters and the seek operation of the above-described steps S1-1 through S1-11 are processed by firmware executed by the MCU.
In the case of transferring control parameters required for read/write control and servo control at a time of a read/write operation to a read/write control part and to a servo control part the transfer is performed by the MCU. Therefore, the MCU is prevented from performing other operations during the transfer of the control parameters, thus causing a problem of deterioration in the performance of the MCU.
FIG. 3 is a timing chart of signals in the conventional magnetic disk unit. FIG. 3(A) shows a servo gate signal, FIG. 3(B) shows a timing of a seek command, FIG. 3(C) shows a timing of a parameter transfer, FIG. 3(D) shows a timing of issuance of a seek command, and FIG. 3(E) shows a timing of the start of processing the command.
As shown in FIG. 3, after the seek command is generated, parameters are transferred. At this time, it takes 50 xcexcs to perform the parameter transfer by firmware. Therefore, as shown in FIG. 3(A), the transfer of the parameters overlaps with a generation timing of the servo gate signal, so that the seek command is delayed by the parameter transfer. Consequently, the read/write performance is deteriorated.
Further, if alterations of the control parameters, or increases and decreases in the control parameters are required, it is necessary to alter a transfer-related portion of the firmware.
Moreover, in the case of a transfer performed by the firmware, an operation of checking completion of the transfer is performed for every byte or word in general. Therefore, a certain waiting period is required after the execution of a transfer. Thus, the operation efficiency is deteriorated in the case of the transfer of the control parameters performed by the firmware. If the performance of a drive, such as the number of revolutions of a spindle motor or a data transfer rate, is improved in the future so as to require a microcontroller of the drive to operate at higher speeds, there will be a problem that a time required for the transfer performed by the firmware causes the deterioration of the operation efficiency of the drive.
The present invention is made in the light of the above-described points, and an object of the present invention is to provide an information storage apparatus which realizes a high-speed transfer of control parameters without deteriorating performance of a control operation, and a method of controlling such an information storage apparatus.
An information storage apparatus of the present invention, which apparatus has storage means for storing control information for controlling a state of access to a recording medium, and control means for controlling the state of access to the recording medium based on the control information, includes transfer control means for transferring the control information stored in the storage means to the control means at a time of accessing the recording medium, the transfer control means including: first retention means for retaining a control information storage address of the storage means where the control information is stored; second retention means for retaining numbers of data of the control information to be transferred to the control means; control information reading means for successively reading out the control information of the numbers of data stored in the second retention means from the control information storage address stored in the first retention means; and data switching means for switching transfer destinations of the control information read out by the control information reading means based on the numbers of data stored in the second retention means.
In the information storage apparatus of the present invention, the data switching means includes counting means for counting down the numbers of data stored in the second retention means every time the control information is read out by the control information reading means, and switching control means for switching the transfer destinations of the control information read out by the control information reading means when a count value of the counter means becomes zero.
In the information storage apparatus of the present invention, the transfer control means is formed integrally on an integrated circuit which forms the control means.
Another information storage apparatus of the present invention, which apparatus has storage means for storing control information for controlling a state of access to a recording medium, and control means for controlling the state of access to the recording medium based on the control information, includes transfer control means which transfers the control information stored in the storage means to the control means at a time of accessing the recording medium, the transfer control means including: first retention means for retaining a control information storage address of the storage means where the control information is stored; second retention means for retaining transfer destination switching information inserted into the control information stored in the storage means; third retention means for retaining transfer termination information stored at an end position of the control information stored in the storage means; control information reading means for successively reading out the control information from the control information storage address stored in the first retention means; and data switching means for comparing the transfer destination switching information retained in the second retention means and the transfer termination information retained in the third retention means with the control information read out by the control information reading means so as to switch transfer destinations of the control information read out from the control information reading means when the control information read out by the control information reading means matches the transfer destination switching information retained in the second retention means, and to terminate a transfer of the control information read out by the control information reading means when the control information read out by the control information reading means matches the transfer termination information retained in the third retention means.
A method of controlling an information storage apparatus according to the present invention by prestoring control information for controlling a state of access to a recording medium and controlling the state of access to the recording medium based on the control information, is characterized in that the control information stored in the storage means is transferred to the control means at a time of accessing the recording medium.
In the method of controlling an information storage apparatus according to the present invention, a control information storage address of the storage means where the control information is stored, and numbers of data of the control information to be transferred are retained, and the control information of the retained numbers of data are successively read out from the retained control information storage address, so that transfer designations of the read control information are switched based on the numbers of data.
In the method of controlling an information storage apparatus according to the present invention, the numbers of data are counted down every time the control information is read out, and the transfer destinations of the control information are switched when a count value becomes zero.
In the method of controlling an information storage apparatus according to the present invention, the control information storage address where the control information is stored, transfer destination switching information inserted into the control information to switch the transfer destinations of the control information, and transfer termination information which indicates an end position of the control information are retained; the control information is successively read out from the control information storage address to be compared with the transfer destination switching information and the transfer termination information; the transfer destinations of the read control information are switched when the read control information matches the transfer destination switching information; and a transfer of the read control information is terminated when the read control information matches the transfer termination information.
According to the information storage apparatus and the method of controlling the same of the present invention, the direct transfers of control information to the transfer designations save time spent in a control information reading operation. Therefore, other operations can be performed efficiently, thus allowing a high-speed reading/writing of information.
Further, according to the information storage apparatus and the method of controlling the same of the present invention, the control information is successively read out from a control information storage address based on the control information storage address and the number of data transferred to each of the transfer designations of the control information, and the transfer designations of the control information are only switched based on the number of data of the read control information. Therefore, distribution control of the control information can be performed easily.
Moreover, according to the information storage apparatus and the method of controlling the same of the present invention, a timing of the switching can be easily detected by counting down the retained number of data at a time of reading out the control information.
Furthermore, according to the information storage apparatus and the method of controlling the same of the present invention, transfer destination switching information is inserted into a given portion of control information so that the control information can be directly transferred to transfer destinations thereof by switching the transfer destinations when the transfer destination switching information is detected, thus saving time spent in a control information reading operation. Therefore, other operations can be performed efficiently, thus allowing a high-speed reading/writing of information.